Marital distance and child variability

The effects of marital distance on the mean and variance of child stature and weight were investigated using the British National Child Development Study data. Children of large marital distance unions had mean values as predicted from mid-parent values and did not exhibit a hybrid vigour effect. However, they did show reduced levels of variability and this effect was most marked at 16 years, although it was also present at 7 and 11 years of age. These results are discussed in terms of large marital distance being associated with high heterozygosity levels, because of geographic variation in gene frequencies.